1. Field of the Invention
This invention relates to filters for cigarettes. In one aspect, it relates to a filter with novel ventilating means therein. In another aspect, the invention relates to a filter cigarette having flow directing grooves therein for mixing with a portion of the tobacco smoke while the remaining portion of the tobacco smoke passes through the filter without mixing the ventilating air.
2. Description of the Prior Art
It is well known in the art of filter cigarettes to provide filters with ventilating means to bring in ambient air to the filter to dilute the smoke stream. The dilution of the smoke stream reduces the quantity of smoke particulates as well as gas phase components which are delivered to the mouth of the smoker. A number of means have been proposed and are utilized for introducing ventilating air into the cigarette. For example, the wrapper for the tobacco in a cigarette can be made from a porous material which allows for introduction of air along the entire length of the cigarette where it mixes with the smoke stream passing therethrough thereby diluting the smoke in the stream prior to entering the smoker's mouth. Also, the cigarette wrapper may be perforated at selected locations along the length of the cigarette which provides ports for the cigarette through which ventilating air enters. Even further, it is known to perforate the wrapper of the filter on the filter end of the cigarette to allow for ventilating air to enter the filter for dilution of the smoke stream. There have also been a number of suggestions for incorporating grooves within the filter plug for the cigarette in order to facilitate the addition of ventilating air into the smoke stream. These include for example U.S. Pat. No. 3,596,663; 3,577,995; 3,572,347; 3,490,461; 1,718,122; 3,788,330; 3,773,053; 3,752,165; 3,638,661; 3,608,561; and, 3,910,288.
There have also been a number of suggestions for incorporating channels within the filter plug for the cigarette in order to facilitate addition of ventilating air into the smoke stream. These include for example U.S. Pat. Nos. 3,416,541; 3,910,288; 3,773,883; 3,581,748; 3,045,680; and, 1,996,990.